80 



NOTE ON SOLORINA BISrORA. 



sed quum transitum nullum vidi, earn seorsim exponere debui." 

 Such a transition state, however, may be seen in Anzi " Exs. 

 Langob.," 46, where the spores are 4-2 nae, and in a specimen from 

 Killin in my own Herb. s. n. S. limbata, where, however, the thecae 

 are usually 4-spored. S. bispora, therefore, cannot with propriety 

 be regarded as distinct from S. limbata (Smmr ft.). This latter also, 

 as it appears to me, has but very slight claims to be separated, 

 otherwise than as a mere variety from S. saccata (Linn.). Certainly 

 as seen in the " Herbarium," and having regard only to the cha- 

 racter of the so-called thallus, it seems sufficiently distinct. An 

 attentive observation, however, of the plant three months ago in 

 Killin, convinced me that an opinion I had previously entertained 

 was correct. There it grows, always associated with saccata, and 

 not only so, but in one and the same specimen occur both the type 

 and the variety. The former evidently passes into the latter through 

 the decay or destruction of the proper thallus, aud the consequent 

 growth or protrusion of an alien thallus. This latter, which is of 

 a gelatinous nature, belongs either to an undeveloped Collema, such 

 as C. cheileum, or a Leptogium such as L. scotinum (minor), (in 

 which case it is Lichen spongiosus. (Sm., E. B.T., 1374.). This is 

 frequently more or less suffused with a whitish lepraria, differing 

 in character, on a microscopic examination, from the pruina which 

 occurs on the thallus of the type. This alien thallus gradually 

 destroys or takes the place of the proper one, leaving only a narrow 

 thalline margin around the apothecia, which becomes at length 

 isidiose or granulose. There can thus, I think, be little doubt that 

 the species stands thus : — Solorina saccata (Linn.), with thecae 

 4 spored and membranaceo-papyraceous continuous thallus ; var. 

 limbata (Smmrft.), with thecae 4, rarely 2-spored, and proper thallus 

 interrupted, and only bordering the apothecia, its place being other- 

 wise usurped by an alien gelatinous (collemoid) thallus. 



CRYPTOGAMIC LITERATURE. 



O'Meara, Rev. E. Recent Researches in the Diatomaceae, 

 No. 7, in " Journal of Botany," for October. 



Niessl, G. V. Beitrage zur Kenntniss der Pilze (continued) 

 in " Hedwigia," No. 9. 



Smith, W. G. On Geaster saccatus, with fig., in " Gardener's 

 Chronicle," p. 1275(1873). 



Kitton, F. Strange habitats of certain species of Diatomacea*, 

 in " Science Gossip," for October. 



Sorby, H. C, F.R.S. On Comparative Vegetable Chromatology 

 (including Cryptogamia), from the " Proceedings of the Royal 

 Society," No. 146, vol. xxi. 



